The present invention generally relates to railroad hopper cars and, more particularly, to an apparatus for controlling operation of a pair of discharge doors on a railroad hopper car.
A common type of railroad freight car is use today is an open top hopper car wherein the commodity carried by the railcar is discharged therefrom through openings provided on an underside of the car. Such cars are used to haul aggregate, iron ore, coal and other commodities. Such cars offer an advantageously economical method of transporting large amounts of a commodity between locations
Such railroad cars generally include a walled enclosure or hopper carried by an underframe of the car. On some hopper cars, the underframe includes a longitudinally elongated centersill or support which is supported, toward opposite ends thereof, by the usual wheeled trucks which ride on tracks or rails. Although the design of the bottom side of the railcar hopper varies considerably, the hopper is typically provided with a plurality of generally funnel shaped discharge openings which extend either parallel to the longitudinal axis of the car (longitudinal openings) or are disposed in pairs on opposite lateral sides of the longitudinal axis of the car (transverse openings). Each type hopper serves a particular need in the railcar industry.
Each railcar is furthermore provided with brakes sets operable in combination with the wheeled trucks. An elongated brake rod or shaft interconnects the brake sets at opposite ends of the car. In some instances, a slack adjuster is provided and extends longitudinally of the car. Suffice it to say, in either instance, the brake rod, shaft or slack adjuster is suspended directly below the centersill of the car. During operation of the car, the path of travel of the brake rod, shaft or slack adjuster is not limited to longitudinal movements. It is important to note, during operation of the railcar, the brake rod, shaft or slack adjuster tends to move both linearly and as well as transversely or laterally relative to the car axis.
To control the discharge of commodity from the hopper, a door assembly is provided in registry with each discharge opening on the car. Each door assembly includes a door which is typically hinged along an upper edge such that, when released, the door gravitationally swings toward an open-position assisted by the commodity moving through the discharge opening.
As will be appreciated, different door operating mechanisms have been proposed to releasably maintain the doors in their closed position. It is important to note, however, such door operating mechanisms are specifically designed to the particular application with which they will find use. For example, a mechanism used to operate longitudinally mounted door assemblies cannot, without substantial redesign, be used to operate transversely arranged door assemblies. Moreover, and primarily because of the disposition of the doors relative to the longitudinal axis of the rail car, mechanisms used to operate longitudinally mounted door assemblies usually require a powered operated driver. As will be appreciated, requiring a powered operated driver to operate such mechanism increases the overall cost of the railcar. Of course, increasing any manufacturing costs is adverse to railcar manufacturers. Thus, those mechanisms used to operate longitudinally mounted door assemblies do not and are not readily useful with those hopper cars having transversely mounted door assemblies.
Designing an apparatus for operating transversely mounted door assemblies on a hopper car also has design challenges. Of course, devices for releasably holding transversely mounted door assemblies in a closed position are known in the prior art. One such device involves using individual hooks or catches in combination with each door assembly. Such prior art design, however, requires a person on each side of the railcar to release the hook or catch whereby allowing the door of the door assembly to swing to an open position. Of course, having a person on each side of the railcar to operate the door operating mechanism is costly and, thus, adverse to the railroad industry. It has also been proposed to join or couple the two doors forming a pair of transversely mounted door assemblies. Such design, however, does not necessarily reduce the persons required to release the doors from their closed position.
Another proposal involves connecting a powered driver to each of the door assemblies as through a linkage arrangement. Besides increasing the cost of the door operating mechanism, such design causes some portion of the linkage arrangement, during at least a portion of its travel, to extend proximate to the path of travel of the brake rod, shaft, or slack adjuster. As will be appreciated, any interference with the brake rod, shaft or lack adjuster movement could prove detrimental to overall operation of the rail car. Accordingly, neither railroad car manufacturers nor the railroad industry are accepting of a door operating mechanism whereby any portion of the device interferes or even possibly interferes with either liner or transverse movements of the brake rod, shaft or lack adjuster. Moreover, some of these heretofore known devices for operating transversely mounted railroad car door assemblies have components which, after the doors are opened, remain in the path of commodity discharge from the hopper car thereby adversely affecting the flow of commodity from the rail car.
Thus, there is a continuing need and desire for an apparatus designed to operate a pair of transversely mounted discharge door assemblies on a railroad hopper car having a centersill without requiring the use of a powered driver and which remains removed from both the linear and transverse paths of travel of the brake rod, shaft, or slack adjuster disposed directly beneath the centersill or support throughout operation of both the apparatus and the rail car.
In view of the above, and in accordance with this invention, there is provided an apparatus for controlling discharge of commodity from a railcar hopper car having a centersill and two laterally spaced door assemblies arranged in registry with two transversely spaced discharge openings on the hopper car. In one form, the door assemblies are joined to each other by an elongated connector such that they move in unison. In one embodiment, the apparatus of the present invention includes an operating shaft rotatable about a fixed axis extending transverse to and beneath the railcar centersill. A linkage system operably connects the operating shaft to the elongated connector to simultaneously push the door assemblies into their closed position in response to rotation of the operating shaft in a first direction and for pulling the door assemblies from their closed position in response to rotation of the shaft in a reverse or second direction.
In a preferred embodiment, the apparatus of the present invention has a modular design whereby facilitating assembly and retrofitting of the apparatus to rail cars in the field. The operating shaft of the apparatus is suspended beneath and, preferably, from the centersill of the railcar and is preferably configured to extend to opposed sides of the rail car. As such, the door operating apparatus of the present invention is operable from either side of the rail car thus, reducing the number of persons required to effect operation of the door assemblies.
The linkage system for the apparatus of the present invention includes a plurality of articulately interconnected links. Preferably, the links are arranged in an overcenter linkage design which serves as a primary lock to releasably maintain the door assemblies in their closed position while preventing the door assemblies from inadvertently opening during transportation of the rail car. In another embodiment, the apparatus of the present invention includes a secondary lock for holding the door assemblies in their closed portion.
In a preferred embodiment, the linkage system includes two laterally spaced linkages arranged on opposite sides of the brake rod, shaft or slack adjuster after the apparatus of the present invention is assembled to the railcar. Each linkage of the linkage system preferably includes a stop for limiting movement of the respective door toward its open position. Moreover, and in a preferred form, each linkage of the linkage system preferably includes a stop for limiting movement of the respective door toward its closed position.
To facilitate assembly and retrofitting of the apparatus of the present invention to rail cars, the linkage system is preferably adjustable. That is, an operative length of at least one of the links of the linkage system can be adjusted to compensate for tolerance variances between systems and between different rail cars.
In view of the above, a principal object of this invention relates to providing an apparatus for operating a pair of transversely mounted discharge door assemblies on a railroad hopper car.
Another object of the present invention is to provide an apparatus for operating a pair of transversely mounted discharge door assemblies and which may be retrofitted to existing railroad hopper cars.
Still another object of the present invention relates to providing an apparatus for operating a pair of transversely mounted discharge door assemblies mounted on railroad hopper car which is economical to manufacture, minimizes the people required to operate the apparatus, and which is operable from either side of the railroad car.
Yet another object of the present invention relates to providing an apparatus capable of operating a pair of transversely mounted discharge door assemblies mounted on railroad hopper and which embodies a linkage system which operates in compression as the door assemblies move toward a closed position.
Still a further object of the present invention relates to providing an apparatus capable of operating a pair of transversely mounted discharge door assemblies mounted on railroad hopper and which ensures the door assemblies remain in position after being releasably closed.
These and other objects, aims, and advantages of the present invention will become more readily apparent from the following detailed description, the drawings and the appended claims.